A combine harvester is a machine that is used to harvest grain crops. The objective is to complete several processes, which traditionally were distinct, in one pass of the machine over a particular part of the field. Among the crops that may be harvested with a combine are wheat, oats, rye, barley, corn, soybeans, and flax or linseed. The waste (e.g., straw) left behind on the field includes the remaining dried stems and leaves of the crop having limited nutrients which may be, for example, chopped and spread on the field as residue or baled for feed and bedding for livestock.
The cut crop may be picked up and fed into the threshing and separating mechanism of the combine, typically consisting of a rotating threshing drum to which grooved steel bars may be bolted. These bars thresh or separate the grains and chaff from the straw through the action of the drum against the concaves, i.e., shaped “half drum,” that may also be fitted with steel bars and a meshed grill, through which grain, chaff and smaller debris may fall, whereas the straw, being too big or long, is carried through to the outlet. The chaff, straw, and other undesired material is returned to the field via a spreader mechanism.
When a harvester, such as a combine, harvests crop, the desirable crop (such as corn kernels for a corn crop) is separated from the remainder of the vegetable matter (e.g. the remainder of the crop plant which can include straw, chaff, husk, cob, etc, depending on the crop being harvested). This remaining vegetable matter is called “residue” or “crop residue”. This residue is typically returned to the field by way of a spreader so that the nutrients can be reclaimed by the field. The spreader is a device at the rear of the combine that typically spreads the residue behind the combine in a substantial uniform manner.
While uniform distribution of residue is often desirable, such as when operating in the middle of a field, uniform distribution is not always ideal. For example, when a combine reaches a section of field where a portion of the cut width of the header does not encounter crop to be harvested (e.g. a portion of the header traverses a portion of the field that has already been harvested) there is no need to return residue from the area currently being harvested to the soil in the area that does not contain crop that is currently being harvested. In this instance, uniform distribution of residue across the entire path of the header is undesirable because the residue from the crop being harvested will be moved away from that portion of the field that contributed the residue. Repeatedly distributing residue from an area currently being harvested to an area that is not contributing to the residue will, over time, move nutrients from the top soil contributing to the residue to other parts of the field that may not be used to produce crop. This can create non-uniform soil conditions in future seasons or can spread nutrients away from the usable growing portion of the field, such as onto roads, into ditches, or anywhere else it may be undesirable to move residue. The prior art does not address this need.
Some prior art spreaders contain an adjustable or configurable mechanism to allow for non-uniform or variable width spread. An operator can use such a spreader to configure the spread of the residue behind a combine. For instance, an operator might configure the residue spread width to be with the cut width of the header that is being used for the current harvest. These spreaders generally require manual adjustment and have not been sufficient for providing dynamic, automatic, or real-time adjustment of the residue distribution.
As wider headers are introduced in the market into practice with harvesters, it becomes more important to have dynamically adjustable spreaders such that the residue from the harvester is distributed in a controlled window. The prior art not address this need.